On Wed, 16 Oct 2002 15:11:34 -0500, Rick Troth <[EMAIL PROTECTED]> wrote:
>NSS is "Named Saved System". >You can take a snap-shot of a running (or runnable) system on VM >which CP (the hypervisor part of VM) will store into a spool file. >You can then IPL that system by name, rather than boot by device. > >The syntax of the IPL command is (gross simplification) > > [hcp] ipl <device> > [hcp] ipl <device> [clear] > [hcp] ipl <name> > [hcp] ipl <name> [parm <parms>] > >where 'hcp' is optional and would be how you issue CP commands >from Linux. If you're on a VM console, there is no 'hcp', >you might prefix with 'cp' instead on CMS, or you >might simply omit that prefix and let 'ipl' >be recognized as a hypervisor command. > >NSS is "virtual ROM" for a named system. >When booting from NSS, the system to be booted comes up instantly, >rather than going through the motions of booting from device. >With care, portions of a Named Saved System can be marked >READ ONLY so that CP (the hypervisor portion of VM) >can share that storage among several virtual machines. > >DCSS is related to NSS. >DCSS is a "Discontiguous Shared Segment", >can be read-only or read-write, can be shared or exclusive, >and appears to the guest operating system as attached storage. >(Need not be in the range of defined memory; that is, it can be >ABOVE the defined storage for your virtual machine.) >DCSS is not the same as NSS but is supported by the >same mechanisms within VM (CP). DCSSs are named, like NSSs, >but are "attached" by a DIAGNOSE code, not booted. The closest Linux parallel is an initrd, a ramdisk image which serves as the initial root disk. john
